ABS Light

I posted the trouble tree for the code's C0251,C0246,C0242,C0252,and C0245.Code C0265 is a code for a internal failure in the ebtcm also. So your best bet is to follow the trouble tree i posted. Here is the description for the code's.
DTC C0241-C0254 or C041-C054

This video will show you how to scan the ABS system.

https://youtu.be/rTtAnsOlZU4

and

https://www.2carpros.com/articles/abs-warning-light-on-easy-repair-guide

Circuit description:
The ABS relay supplies battery voltage to six valve solenoids (right front dump/isolation, left front dump/isolation, and rear dump/isolation). The EBCM microprocessor applies the grounds needed to activate each solenoid. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When a solenoid is commanded off the feedback voltage is high. When a solenoid is commanded on, the feedback voltage is low.

Conditions for Running the DTC

* The ignition is on.
* The vehicle speed is greater than 6 km/h (4 mph) .

Conditions for Setting the DTC
The EBCM detects an internal malfunction.

Action Taken When the DTC Sets
C0241, C0242, C0245, C0246, C0251, C0252, C0253, C0254
If equipped, the following actions occur:

* The EBCM disables the DRP/ABS.
* The ABS indicator turns on.
* The red Brake warning indicator turns on.

C0243, C0244, C0247, C0248
If equipped, the following actions occur:

* The EBCM disables the ABS.
* The ABS indicator turns on.

Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids
An intermittent open/shorted solenoid DTC can be set by several different internal EBCM problems. Replace the EBCM if an open/shorted solenoid DTC continues to set intermittently.

This is a common problem with the ABS control module we replace them all the time.

Here is a guide and a video on how the job is done.

https://www.2carpros.com/articles/how-to-replace-a-abs-controller

and

https://youtu.be/lUotkKXG9dY

You can find one on Amazon for 615.00 Delco unit

https://www.amazon.com/gp/product/B01E6GA9OU/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=2carprcom-20&creative=9325&linkCode=as2&creativeASIN=B01E6GA9OU&linkId=6778b295cb1d5efa7a28202914a62b6a

Please let us know what happens.

Cheers, Ken

Brakes problem
2001 Chevy Silverado V8 Four Wheel Drive Automatic 153000 miles

The ABS and BRAKE panel warning lights are on constantly. My dealer tells me that the computer is at fault, and would cost $1100 to repair. My experience with Jet ABS systems has been that the wheel generators are almost always at fault. Also the brakes 'snub' almost like a bent wheel feeling when going down hill. I don't want to pay $1100 for a computer is this the problem?

Depends on the codes it is throwing, but the GM ABS units have problems with the power relays and the such and they are built into the EBCU. The odds of it being the computer ar pretty good

Brakes problem
2001 Chevy Silverado V8 Four Wheel Drive Automatic 116000 miles

both abs and brake light are on. i know its a recall and a problem in winter states where salt and sand cause corrosion, i know it has brake pedal and brakes do work,i understand some how it has something to do with the speed sensors. this problem interferes with the brake hydrolics. no brake fluid loss! all brake lines are good

There are more than just wheel sensor issues with that system.You need to have the ABS system scanned for codes to know why the lights are on.It has disabled the ABS for now, so yes you have brakes, but no ABS.With a failure code we can see exactly why the light is on

Brakes problem
2001 Chevy Silverado V8 Two Wheel Drive Automatic 80000 miles

The brake light comes on and the ABS light comes on not right away but after you drive the truck a coulpe of miles just. Just changged brkes and also on of the calipers That whrer sticking hat problems in the past when the bearings went bad and causd the abs light to come on but every thing looks fin unless it it just hhe sensor going back .Or what else could be causing this to happin and making he brake light come on aslo. ANY HELP WOULD GREATLY BE APRICIATED THANK YOU!!!!

If the brake fluid is full, chances are you have either a bad sensor or wiring issue at the sensor. Have you ever had the computer scanned when the ABS light is on?

No I have not had it scanned but I will. I have had. to change the hub assemble where the ABS sensor is located. I have seen the bearings go out and eat up the sensor causing it to make the light come on but not both lights at the same time. Also I believe that water made the sensor go of befor on a different truck but it seemed like the light went off once it dried out. Is there any way to tell witch sensor it is, does the scanner tell you im guessing not unles it is a TECH II . Ill check and le you know what i found. THANK YOU.

It could be something as simple as low brake fluid. However, the scanner should direct you to the correct component that is causing the light.

Check it out and let me know what you find.

Joe

The first thing to do is get the truck scanned for diagnostic trouble codes in the abs module, retrieve the codes and that will a starting point for diagnoses.

Electrical problem
2001 Chevy Silverado V8 Two Wheel Drive Automatic 134785 miles

I get the "BRAKE" and "ABS" lights come at the same time on for no reason that I can think of. It may do it is I go over a bump or while I am driving along. Every thing appears to be OK with the brakes. It will not go out until you turn the key off and back on. Some times it will stay off for a day then sometimes it comes on right away when you start to drive. There are no codes to be read for this. I've had several suggestions as to what it maybe but nothing for sure.

TEST A: ABS INDICATOR ALWAYS ON
Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING. After performing diagnostic system check, go to next step.
Turn ignition off for 5 seconds. Turn ignition on and observe ABS indicator light. If indicator light illuminates for 2 seconds then turn off, problem is intermittent. If indicator light does not illuminate for 2 seconds or does not turn off, go to next step.
Using scan tool, select instrument panel cluster special functions menu. Command ABS indicator light off. If indicator light turns off when commanded, go to step 5. If indicator light does not turn off when commanded, go to next step.
Replace instrument panel cluster. After replacing instrument panel cluster, go to step 6.
Replace EBCM. After replacing EBCM, go to next step.
Turn ignition off for 5 seconds. Turn ignition on and observe ABS indicator light. If indicator light illuminates for 2 seconds then turn off, system is okay. If indicator does not illuminate for 2 seconds or illuminates but does not turn off, go to step 3.

Brakes problem
2000 Chevy Silverado V8 Four Wheel Drive Automatic 112230 miles
----------------------------------------------------------------
My 2000 Silverado has a problem with the ABS light lighting up on an intermittent basis. It will be off when I first start out then both the regular brake light and the ABS brake light will come on on my light panel. Is there a way to clean the ABS sensors in the brake system to relieve this problem?

You need to check the trouble codes for the abs first. Let me know what the codes are.

Brakes problem
1999 Chevy Silverado V8 Two Wheel Drive Automatic 130785 miles

My abs and Brake light comes on once and a while, i have checked all brakes and they seem fine. Good pad and good rotors. nothing sticking they seem to be working just fine. The abs and brake light will come on in all different situations, from driving down bumpy roads, to braking fast, to just driving down the expressway on cruise control. i was told that it may be my high mount brake light in the back but it also seems to be working fine. any ideas would be helpful. thanks and have a great day.

ABS system :*** have it scanned for codes ***

only way you can find out why the light is coming
very common is brake light switch or front wheel bearing and sensor
need to have the codes

thank you i will have the codes checked.

Let me know what you have for codes
(when you do )

1999 Chevy Silverado V8 Four Wheel Drive Automatic 100000 miles

I have had sporadic abs warning llights, I have replaced the front hub including new abs sensors. Recently the abs light is on constantly, I do not have any trouble codes. I have regrounded the ground connection at the frame under the drivers side door and in the front drivers side ground but I still have an abs warning light. Any other suggestions ?

You're going to have to use a scanner to communicate with the module. There will be an option for 'ABS' on the scan tool. You'll have to start there. I have NO WAY to know which way to steer you without getting the info from the module. There's really not too much involved in the ABS system so, usually, they're pretty easy to diagnose. If the ABS light is ON, there's a code somewhere in the ABS module. It will tell you if it's a LF wheel speed sensor or RF, or vehicle speed sensor, etc.. Get that info and get back with me and we'll fix it!

In response to JasonRay, my cheap scanner does not have an abs function, can I get this done at Auto Zone

No you can not. They do not have the proper equipement to scan other modules.

He's right, don't take it to Autozone. And, if you do, don't buy the parts they're going to try to sell you yet. It'll have to go to a shop that has a decent scanner to access the ABS info. The scanner will tell you why the light is on. Without that info, we'll just be throwing parts at it til we get it right. When you DO get the problem fixed, the light will go out on it's own when you start to drive the truck. It runs a 'self test' each time the truck is started. If it's a wheel speed sensor, and the light goes out when you start the truck, it will come back on as soon as you start to drive the truck, when it monitors the wheel speeds. Some scanners will let you watch the speed of each wheel as you drive it. Mine is an OTC Nemesis and it will do it. I wish I could help you more but without access to the ABS info, it's difficult. But if you DO take it somewhere and get that info, I'll be glad to help you more.

Both the ABS and Brake lights sometimes stay on after starting the truck. One mechanic tried to fix it but said I would need to replace a part. The part cost more than the value of the truck. A second mechanic had a go at it and the problem seemed solved but now it has come back. I can live with it but have safety concerns.

Any suggestions?

Thanks.

The yellow ABS warning light will not cause the red Brake light to turn on, but the red Brake light will turn the yellow ABS light on. That's because the ABS Computer only knows something is wrong with the base brake system but it doesn't know what. That problem could result in an inability to run the anti-lock function properly.

That means you need to look at the red warning light, and there's only three switches at most that affect it. The first, if your truck has it, is a low-fluid level switch in the master cylinder. If the fluid is low, do not fill it. Add just enough to turn the light off. The fluid is low either because there's an external leak that must be addressed or the front disc brake pads are worn and need to be replaced. Replacing worn brake pads requires pressing the pistons back into the calipers, and that pushes all the brake fluid behind them back up into the reservoir. If a do-it-yourselfer or inexperienced mechanic has previously filled the brake fluid, it's going to overflow and run all over creating a mess, and damaging any painted surfaces.

The second switch is for the parking brake. Be sure the pedal is releasing fully. The last switch is the pressure-differential switch. That may be in the hydraulic controller for the ABS system, otherwise it is in the middle of the brass combination valve that sits on the frame rail right under the master cylinder. On vehicles without anti-lock brakes, you can follow the two steel lines from the master cylinder to that valve. Simply unplug that switch to see if the red warning light goes off. If it does, one of the two hydraulic systems didn't build pressure as fast as the other one. Typically that's due to a leak. That valve is spring-loaded on GM and Chrysler vehicles but sometimes it sticks. A quick hard jab on the brake pedal usually releases it.

Hi and thanks for the reply. Took me a while to find my records and this is what they show.
Replaced front brake pads and rotor.
Codes were scanned

If this did not work I was told I needed an Electronic Brake Control Module.

The mechanic needs to list the specific fault codes, otherwise that's like your doctor telling you, "well, we ran some tests". Wouldn't you like to know the results of those tests?

Again, an ABS problem won't turn on the red "Brake" warning light. If that one is on, look at the three things I mentioned earlier. You can simply unplug each of those three switches to see which one makes the red light go off.